Both warning and warning-message are pretty low on questions, and both cover practically identical area. I don't have enough points (whatever they are) to propose synonym myself, so posting here.
I think warning should be merged with warning-message, it point only the warning message.– BalaSep 11, 2013 at 16:15
2I don't think we really need this tag to begin with...– mpdonadio ModSep 12, 2013 at 17:59
Instead of making the two tags synonym, I have deleted them, since I agree with MPD.
I don't think we have users who answer questions about warning messages, and just to those questions. The fact then that some code is causing an warning message is not so relevant for answering to need its own tag.